TWI494665B - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. More specifically, it relates to a liquid crystal alignment agent which exhibits a high voltage retention ratio and exhibits good scorch characteristics at any use temperature, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element including the film.

In the past, a transparent conductive film was used to form a layer having a positive dielectric anisotropic nematic liquid crystal between two substrates of a liquid crystal alignment film forming surface as a sandwich cell, and the liquid crystal molecules were long. A TN type liquid crystal display element having a TN (Twisted Nematic) type liquid crystal cell with a shaft twisted from one substrate to the other substrate by 90 degrees.

In addition, there is also a STN (Super Twisted Nematic) type in which the long axis of the liquid crystal molecules is continuously twisted by 180 degrees or more between the substrates by the addition of the palm reagent. Liquid crystal display element. Recently, a nematic liquid crystal layer or a spiral axis having a homeotropically aligned state of a negative dielectric anisotropic between the opposite substrates forms a cholesteric liquid crystal layer in a state parallel to the substrate normal, and is added to the liquid crystal layers. A guest-host reflective liquid crystal display element of a pigment has also been developed. The alignment of the liquid crystals in these liquid crystal display elements is generally expressed by a liquid crystal alignment film which is subjected to rubbing treatment. Among them, as a material constituting a liquid crystal alignment film of a liquid crystal display element In the past, polyimine, polyamide, and polyester have been known. In particular, polyimine is widely used for liquid crystal display elements because of its excellent heat resistance, affinity with liquid crystals, mechanical strength, and the like.

In the past, we have developed a high-voltage display rate, high reliability, and low performance for the purpose of highly developing high-performance display elements, such as high-definition display quality improvement and low-power consumption of liquid crystal display devices. A liquid crystal display element having a scorch characteristic. However, in recent years, in addition to the past transmission type, the utilization range of the reflective type or semi-transmissive liquid crystal display element has also expanded. As a result, the required performance of the liquid crystal alignment film is also increasingly strict. In particular, in the liquid crystal display element for the purpose of low scorch marks, the demand for the scorch property is severe, and it is difficult to say that the performance of the liquid crystal display element has been sufficient in the past. A liquid crystal alignment film formed of a polyaminic acid precursor of a polyimine precursor or a quinone imine polymer having a structure obtained by dehydration ring closure, and a liquid crystal display film using the liquid crystal alignment film In the case of an element, even if it has excellent liquid crystal alignment ability and sufficient voltage retention and signalability are obtained, an alignment agent which deteriorates the scorch property due to the use temperature is often present.

An object of the present invention is to provide a polymer having a prolyl bond unit and a quinone bond unit as a polyimine precursor useful for a liquid crystal alignment film, which can exhibit a high voltage retention ratio, and A liquid crystal alignment agent exhibiting low scorch characteristics at any use temperature.

Another object of the present invention is to provide a liquid crystal alignment film having the above-described excellent properties obtained from the above liquid crystal alignment agent.

Still another object of the present invention is to provide a liquid crystal display element comprising the liquid crystal alignment film of the present invention.

Still other objects and advantages of the present invention will be apparent from the following description.

According to the first aspect of the present invention, the guanidinium bond unit represented by the following formula (I-1) and the quinone bond unit represented by the following formula (I-2) can be obtained by the first invention of the present invention. The polymer, wherein the ratio of the number of units of the quinone bond is 10 to 80% for the total number of bond units of the guanidine bond unit and the quinone bond unit, and the following formula (A) The imidazole compound shown is a characteristic liquid crystal alignment agent.

Wherein P ¹ is a tetravalent organic group and Q ¹ is a divalent organic group.

Wherein P ² is a tetravalent organic group and Q ² is a divalent organic group.

Wherein R ¹ , R ² and R ³ are independently a hydrogen atom or an alkyl group, and n is an integer of 0 to 3. )

The above objects and advantages of the present invention can be attained by the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention.

The above objects and advantages of the present invention can be attained by the liquid crystal display device comprising the liquid crystal alignment film of the present invention.

The best form of implementing the invention

The invention will be described in detail below.

The liquid crystal alignment agent of the present invention contains a polymer having a bond unit (or repeating unit) represented by the above formula (I-1) and a bond unit (or repeating unit) represented by the above formula (I-2) and the above formula. The imidazole compound shown in (A).

The polymer may be a mixture of a polylysine having a repeating unit represented by the above formula (I-1) and a polyimine having a repeating unit represented by the above formula (I-2), and may have the above A repeating unit represented by the formula (I-1) and a partially fluorinated polymer of the repeating unit represented by the above formula (I-2).

The above polylysine can be obtained by subjecting a tetracarboxylic dianhydride to a diamine compound by ring-opening polymerization, and the polyimine is generally obtained by dehydration ring closure of polyamic acid. Part of the quinone imine polymer is generally obtained by combining a proline prepolymer with a quinone imine prepolymer to synthesize a block copolymer.

<Polyuric acid and polyimine> [tetracarboxylic dianhydride]

a tetravalent organic group represented by P ¹ in the repeating unit (proline bond unit) represented by the above formula (I-1), and a repeating unit represented by the above formula (I-2) (indenine bond unit) The tetravalent organic group represented by P ^{2 is a} group derived from a tetracarboxylic dianhydride. Examples of the tetracarboxylic dianhydride include at least any of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-A. 5-(4-hydro-2,5-dioxo-3-furan)-naphtho[1,2-c]-furan-1,3-dione, 1,2,3,4-cyclobutane Alkanetetracarboxylic dianhydride is preferred.

Examples of the other tetracarboxylic dianhydride used for the synthesis of polyamic acid include butane tetracarboxylic dianhydride and 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid. Acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic acid Dihydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1 , 2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid Dihydride, 2,3,4,5-tetrahydrofuran tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furan )-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5 -dioxo-3-furan)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5-ethyl-5 -(tetrahydro-2,5-dioxo-3-furan)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-six Hydrogen-7-methyl-5-(tetrahydro-2,5-dioxo-3-furan)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a ,4,5,9b-hexahydro-7-ethyl-5-(tetrahydro-2,5-dioxo-3-furan)-naphtho[1,2-c]-furan-1,3- Diketone, 1,3,3 a,4,5,9b-hexahydro-8-ethyl-5-(tetrahydro-2,5-dioxo-3-furan)-naphtho[1,2-c]-furan-1,3 -dione, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl-5-(tetrahydro-2,5-dioxo-3-furan)-naphtho[1] ,2-c]-furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran)-3-methyl-3-cyclohexane-1,2-dicarboxylic dianhydride, double ring [2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxobicyclo[3.2.1]octane-2,4-dione-6-spiro-3 '-(Tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furan)-3-methyl-3-cyclohexane-1,2-dicarboxyl Anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2:3,5:6-dianhydride, 4,9-dioxatriazole [5.3.1.0 ^2,6 ]undecane-3 , 5,8,10-tetraketone, an aliphatic or alicyclic tetracarboxylic dianhydride such as a compound represented by the following formulas (I) and (II);

(wherein R ⁴ and R ⁶ represent a divalent organic group having an aromatic ring, R ⁵ and R ⁷ represent a hydrogen atom or an alkyl group, and each of R ⁵ and R ^{7 in} the plural may be the same or different.)

3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenylfluorene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylate Acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-dimethyl Diphenyl decane tetracarboxylic dianhydride, 3,3',4,4'-tetraphenylnonane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 4,4' - bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl phthalic anhydride, 4,4'- Bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylidene dipeptide dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'- Biphenyltetracarboxylic dianhydride, bis(peptide acid)phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylpeptide) dianhydride, m-phenylene-bis(triphenylpeptide) Acid) dianhydride, bis(triphenylpeptide)-4,4'-diphenyl ether dianhydride, bis(triphenylpeptide)-4,4'-diphenylmethane dianhydride, ethylene glycol - bis(p-benzoate), propylene glycol-bis(trimellitic acid ester), 1,4-butanediol-bis(trimellitic acid ester), 1,6-hexanediol-double ( Pyromellitate), 1,8-octanediol-bis(trimellitic acid ester), 2,2-bis(4-hydroxyphenyl)propane-bis(trimellitic acid ester), the following An aromatic tetracarboxylic dianhydride such as a compound represented by each of the formulae (1) to (4). These other tetracarboxylic dianhydrides may be used alone or in combination of two or more.

Among them, butane tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 5-(2,5-dioxotetrahydrofuran)-3-methyl-3-ring Hexane-1,2-dicarboxylic dianhydride, bicyclo[2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxobicyclo[3.2.1] octane Alkane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), the compound of the above formula (I), the following formula (5) to (7) Among the compounds shown in the above formula and the compound represented by the following formula (8) in the compound represented by the above formula (II), it is preferred from the viewpoint of exhibiting good liquid crystal alignment.

[diamine compound]

Examples of the diamine compound used for the synthesis of polyamic acid or polyimine include p-phenylenediamine, m-phenylenediamine, and 4,4'-diaminediphenyl. Methane, 4,4'-diamine diphenylethane, 4,4'-diamine diphenyl sulfide, 4,4'-diamine diphenyl sulfonium, 3,3'-dimethyl-4 , 4'-diamine biphenyl, 4,4'-diamine benzanilide, 4,4'-diamine diphenyl ether, 1,5-diamine naphthalene, 2,2'-dimethyl- 4,4'-diamine biphenyl, 5-amine-1-(4'-aminophenyl)-1,3,3-trimethylindan, 6-amine-1-(4'-aminophenyl -1,3,3-trimethylindan, 3,4'-diamine diphenyl ether, 3,3'-diamine benzophenone, 3,4'-diamine benzophenone, 4,4'-diamine benzophenone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)benzene Hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]anthracene, 1,4-bis(4) -aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 9,9-bis(4-aminephenyl) -10-hydroquinone, 2,7-diamine oxime, 9,9-dimethyl-2,7-diamine oxime, 9,9-bis(4-aminophenyl)anthracene, 4,4'-stretch Methyl-bis(2-chloroaniline), 2,2',5,5'- Chloro-4,4'-diamine biphenyl, 2,2'-dichloro-4,4'-diamine-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy- 4,4'-diamine biphenyl, 1,4,4'-(p-phenylphenylisopropylene)diphenylamine, 4,4'-(m-phenylphenylidene)diphenylamine, 2,2'-bis[4-(4-Amine-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4,4'-diamine-2,2'-bis(trifluoromethyl Biphenyl, 4,4'-bis[(4-amine-2-trifluoromethyl)phenoxy]-octafluorobiphenyl, 4-(4'-trifluoromethoxybenzylideneoxy) An aromatic diamine such as cyclohexyl-3,5-diamine benzoate; 1,1-m-xylylenediamine, 1,3-propanediamine, tetramethylammonium, pentamethylamine Amine, hexamethylenediamine, heptamethylamine, octamethylamine, hexamethylenediamine, 4,4-diamine heptamethylenediamine, 1,4-diamine ring Hexane, isophorone diamine, tetrahydrobicyclopentadienyldiamine, hexahydro-4,7-methanol decane dimethylenediamine, tricyclo[6.2.1.0 ^2,7 ] - undecene dimethyl diamine, 4,4'-methyl bis(cyclohexylamine), 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl) Aliphatic and alicyclic diamines such as cyclohexane; 2,3-diamine pyridine, 2,6-diamine pyridinium Pyridine, 3,4-diamine pyridine, 2,4-diamine pyrimidine, 5,6-diamine-2,3-dicyanopyrazine, 5,6-diamine-2,4-dihydroxypyrimidine, 2 , 4-diamine-6-dimethylamine-1,3,5-triazine, 1,4-bis(3-aminopropyl)piperazine, 2,4-diamine-6-isopropoxy- 1,3,5-triazine, 2,4-diamine-6-methoxy-1,3,5-triazine, 2,4-diamine-6-phenyl-1,3,5-three Pyrazine, 2,4-diamine-6-methyl-s-triazine, 2,4-diamine-1,3,5-triazine, 4,6-diamine-2-ethylene-s-triazine , 2,4-diamine-5-phenylthiazole, 2,6-diamine oxime, 5,6-diamine-1,3-dimethyluracil, 3,5-diamine-1,2, 4-triazole, 6,9-diamine-2-ethoxy acridine propanoate, 3,8-diamine-6-phenylphenanthridine, 1,4-diamine piperazine, 3,6 -diamine acridine, bis(4-aminophenyl)aniline, 3,6-diaminecarbazole, N-methyl-3,6-diaminecarbazole, N-ethyl-3,6-diamine Carbazole, N-phenyl-3,6-diamine carbazole, N,N'-bis(4-aminophenyl)-benzidine and compounds of the following formulas (III) to (VI) a diamine having two primary amine groups in the molecule and a nitrogen atom other than the tertiary amine group; (wherein R ⁸ represents a monovalent organic group having a ring structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine, and X represents a divalent organic group.)

(wherein, X represents a divalent organic group having at least one ring structure of a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine, R ⁹ represents a divalent organic group, and X in the plural is present For the same or different.)

a monosubstituted phenyldiamine represented by the following formula (V); a diamine organooxane represented by the following formula (VI); (wherein R ¹⁰ represents a divalent organic group selected from the group consisting of -O-, -COO-, -OCO-, -NHCO-, -CONH-, and -CO-, and R ¹¹ represents a steroid skeleton selected from the group consisting of steroids, trifluoromethyl a monovalent organic group having a radical of a fluorine group or an alkyl group having a carbon number of 6 to 30.)

(wherein R ¹² represents a hydrocarbon group having 1 to 12 carbon atoms, and R ¹² each having a plural number may be the same or different, p is an integer of 1 to 3, and q is an integer of 1 to 20.)

The compounds represented by the following formulas (9) to (13) and the like can be given. These diamine compounds may be used singly or in combination of two or more.

(where y is an integer from 2 to 12, and z is an integer from 1 to 5.)

Among them, p-phenylenediamine, 4,4'-diaminediphenylmethane, 4,4'-diaminediphenyl sulfide, 1,5-diamine naphthalene, 2,7-di Amine, 4,4'-diamine diphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 9,9-bis(4-aminophenyl)anthracene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-phenylene) Diisopropylidene)diphenylamine, 4,4'-(m-phenylphenyldiisopropylidene)bisbenzene Amine, 1,4-cyclohexanediamine, 4,4'-methyl bis(cyclohexylamine), 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis (4) -aminophenoxy)biphenyl, 4-(4'-trifluoromethoxybenzylideneoxy)cyclohexyl-3,5-diamine benzoate, the above formula (9) to (13) Each of the indicated compounds, 2,6-diamine pyridine, 3,4-diamine pyridine, 2,4-diaminopyrimidine, 3,6-diamine acridine, 3,6-diamine carbazole, N- Methyl-3,6-diamine carbazole, N-ethyl-3,6-diamine carbazole, N-phenyl-3,6-diamine carbazole, N,N'-bis(4-amine a compound represented by the following formula (14) and a compound represented by the following formula (15) in the compound represented by the above formula (IV) in the compound represented by the above formula (III); And dodecyloxy-2,4-diamine benzene, pentadecyloxy-2,4-diamine benzene, hexadecyloxy-2,4- in the compound represented by the above formula (V) Diamine benzene, octadecyloxy-2,4-diamine benzene, dodecyloxy-2,5-diamine benzene, pentadecyloxy-2,5-diamine benzene, hexadecane a compound represented by each of the following formulas (16) to (22), and a compound represented by the above formula (VI), a bis- 2,5-diamine benzene, an octadecyloxy-2,5-diamine benzene 1,3-bis(3-aminopropyl)- in the compound Silicon preferably dimethyl siloxane.

[Synthesis of polylysine]

The ratio of the use of the tetracarboxylic dianhydride to the diamine compound for the synthesis reaction of polylysine, and the anhydride group of the tetracarboxylic dianhydride is 0.5 to 2 equivalents for 1 equivalent of the amine group contained in the diamine compound. The ratio is preferably, more preferably 0.7 to 1.2 equivalents.

The synthesis reaction of the polyamic acid is carried out in an organic solvent, preferably at a temperature of from -20 to 150 ° C, more preferably from 0 to 100 ° C. In addition, as the organic solvent, only the synthesized polylysine may be dissolved, and it is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N. Aprotic polar solvents such as N-dimethylformamide, dimethyl hydrazine, γ -butyrolactone, tetramethyl urea, hexamethylphosphonium; m-cresol, xylenol, phenol, A phenolic solvent such as a halogenated phenol. Further, the amount (a) of the organic solvent used is preferably such that the total amount (b) of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 30% by weight based on the total amount (a+b) of the reaction solution.

[weak solvent]

In the organic solvent, an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, a hydrocarbon or the like of a weak solvent of polyproline is used in combination in a range in which the produced polyamine is not precipitated. Specific examples of the related weak solvent include, for example, a Alcohol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, Methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, diethyl oxalate, Diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol- N-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether , diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1 ,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, isoamyl propionate, isoamyl isobutyl Acid ester, diisoamyl ether, and the like.

As described above, a reaction solution in which polylysine is dissolved can be obtained. The reaction solution is poured into a large amount of a weak solvent to obtain a precipitate, and the precipitate is dried under reduced pressure, or the reaction solution can be distilled off under reduced pressure in a distiller to obtain a polyamine. Further, the polylysine may be purified by dissolving the polylysine in an organic solvent, followed by a step of precipitating with a weak solvent or a step of distilling off under a reduced pressure in a retort.

[醯i-imidized polymer]

The quinone imidized polymer constituting the liquid crystal alignment agent of the present invention can be prepared by dehydration ring closure as described above. The polyimine used in the present invention may be partially dehydrated with a ruthenium iodide ratio of less than 100%. Closed looper. The "yttrium imidization ratio" is a value in which the ratio of the repeating unit of the quinone ring or the isoindole ring is expressed as a percentage in the total repeating unit of the polymer. An alignment agent containing a ruthenium imidized polymer having a ruthenium iodide ratio of 10 to 80% is particularly useful for evaluation of a high voltage holding ratio when used in a TFT type device. The dehydration ring closure of polylysine can be carried out by (i) heating the poly-proline acid or by dissolving the poly-proline in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst. It is necessary to carry out the heating method.

The reaction temperature in the above (i) method of heating the polyamic acid is preferably from 50 to 200 ° C, more preferably from 60 to 170 ° C. When the reaction temperature is less than 50 ° C, the dehydration ring closure reaction is difficult to proceed sufficiently, and when the reaction temperature exceeds 200 ° C, the molecular weight of the obtained ruthenium iodide polymer decreases.

On the other hand, in the method of adding a dehydrating agent and a dehydration ring-closing catalyst to the solution of the poly-proline in the above (ii), as the dehydrating agent, for example, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 moles per 1 mole of the polyamine. Further, as the dehydration ring-closing catalyst, for example, a tertiary amine such as pyridine, trimethylpyridine, lutidine or triethylamine can be used. However, it is not limited to this. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Further, examples of the organic solvent used in the dehydration ring closure reaction include organic solvents exemplified for the synthesis of polyglycine. The reaction temperature of the dehydration ring closure reaction is preferably from 0 to 180 ° C, preferably from 10 to 150 ° C. Further, for the reaction solution thus obtained, the oxime imidization can be purified by performing the same operation as the purification method of polylysine. polymer. The ruthenium amination rate can be obtained by the following method.

Method for determination of ruthenium imidization ratio of ruthenium iodide polymer

The ruthenium iodide polymer was dried under reduced pressure at room temperature, dissolved in dimethyl hydrazine, and tetramethyl decane was used as a reference material, and ¹ H-NMR was measured at room temperature by the following. The formula shown in the formula (ii) is obtained.

Yttrium imidation rate (%) = (1-A ¹ /A ² ×α)×100------(ii)

A ¹ : peak area of protons from NH group (10 ppm)

A ² : peak area from other protons

α: the ratio of the number of other protons in a polymer precursor (poly-proline) to one NH matrix

[end modification]

The polylysine and the ruthenium iodide polymer may also be those having a molecular weight adjusted end modification. By using the terminal-modified polymer, the coating properties and the like of the liquid crystal alignment agent can be improved without impairing the effects of the present invention. Such a terminal modification type can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound, or the like to a reaction system when synthesizing polyamic acid. Here, examples of the acid monoanhydride include maleic anhydride, peptide anhydride, itaconic anhydride, n-decyl succinic anhydride, n-lauroyl succinic anhydride, n-tetradecyl succinic anhydride, and n-hexadecyl group. Succinic anhydride and the like. Further, examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, and n-hexyl Amine, n-pentylamine, n-octylamine, n-decylamine, n-decylamine, n-undecylamine, n-laurylamine, n-tridecylamine, n-tetradecylamine, n- Pentadecylamine, n-hexadecaneamine, n-heptadecaneamine, n-octadecylamine, n-eicosylamine, and the like. Further, examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

Solution viscosity

When the polymer used in the alignment agent of the present invention is used as a 10% by weight solution, it has a temperature of 20 to 800 mPa. The viscosity of s is better, with 30~500mPa. The viscosity of s is better.

Further, the solution viscosity (mPa.s) of the polymer was measured using a predetermined solvent, and the solution diluted to the solid content concentration was measured at 25 ° C using an E-type rotary viscometer.

<Imidazole compound>

The liquid crystal alignment agent of the present invention contains the imidazole compound represented by the above formula (A). The imidazole compound may be used alone or in combination of two or more. In the above formula (A), R ¹ , R ² and R ³ each independently represent a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Further, n is an integer of 0 to 3, preferably 0 or 1. The imidazole compound is, for example, a preferred example of each compound represented by the following formulas (23) to (27). The addition ratio of these imidazole compounds is preferably from 0.1 to 40 parts by weight based on 100 parts by weight of the polymer.

<Liquid alignment agent>

The liquid crystal alignment agent of the present invention is composed of the above polyamic acid and/or polyimine, the above imidazole compound, and other components added arbitrarily dissolved in an organic solvent. In the polymer constituting the liquid crystal alignment agent of the present invention, the ratio of the number of units of the quinone imine bond is 10 to 80% for the total number of bond units of the guanine bond unit and the quinone bond unit.

The organic solvent constituting the liquid crystal alignment agent of the present invention is exemplified as the same solvent exemplified for the synthesis reaction using polyglycine. Further, it can be suitably selected and used as the same weak solvent which can be used in combination with the synthesis reaction of poly-proline. Examples of the particularly preferred organic solvent used in the liquid crystal alignment agent of the present invention include N-methyl-2-pyrrolidone, γ -butyrolactone, γ-butylide, and N,N-dimethylformamidine. Amine, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionic acid Ester, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n -butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, isoamyl propionate, isoamyl isobutyl Acid ester, diisoamyl ether, and the like. These can be used individually or in mixture of 2 or more types. A particularly preferable solvent composition is a composition obtained by combining the above solvents, a polymer is not precipitated in the alignment agent, and a surface tension of the alignment agent is in a range of 25 to 40 mN/m.

The solid content concentration in the liquid crystal alignment agent of the present invention can be selected in consideration of viscosity, volatility, and the like. It is preferably in the range of 1 to 10% by weight. In other words, the liquid crystal alignment agent of the present invention is applied to the surface of the substrate to form a coating film as a liquid crystal alignment film. However, when the solid concentration is less than 1% by weight, the film thickness of the coating film is too small, and it is difficult to obtain a good liquid crystal alignment. membrane. When the solid content concentration exceeds 10% by weight, the film thickness of the coating film is too large, and it is difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent is increased to easily deteriorate the coating properties. Further, the particularly preferable range of the solid content concentration differs depending on the method used when the liquid crystal alignment agent is applied to the substrate. For example, it is particularly preferable to carry out the range of 1.5 to 4.5% by weight by the spin coating method. When the printing method is carried out, the solid content concentration is in the range of 3 to 9 wt%, whereby the solution viscosity is 12 to 50 mPa. The range of s is particularly good. When the inkjet method is carried out, the solid content concentration is in the range of 1 to 5% by weight, whereby the solution is viscous. Degree is 3~15mPa. The range of s is particularly good. Further, the temperature at which the liquid crystal alignment agent of the present invention is prepared is preferably 0 to 200 ° C, more preferably 20 to 60 ° C.

In the liquid crystal alignment agent which forms the liquid crystal alignment film of the present invention, a compound having at least one epoxy group in the molecule (hereinafter also referred to as "epoxy group-containing compound" is contained from the viewpoint of improving adhesion to the surface of the substrate. ") is better. Examples of the epoxy group-containing compound include ethylene glycol diepoxypropyl ether, polyethylene glycol diepoxypropyl ether, propylene glycol diepoxypropyl ether, and tripropylene glycol diepoxypropyl ether. Polypropylene glycol diepoxypropyl ether, neopentyl glycol diepoxypropyl ether, 1,6-hexanediol diepoxypropyl ether, glycerol diepoxypropyl ether, 2,2-di Bromo neopentyl glycol diepoxypropyl ether, 1,3,5,6-tetraepoxypropyl-2,4-hexanediol, N,N,N',N'-tetraepoxy Propyl-m-xylenediamine, 1,3-bis(N,N-diglycidylmethyl)cyclohexane, N,N,N',N'-tetraepoxypropyl-4,4 Preferred examples of '-diamine diphenylmethane, N,N,-diepoxypropyl-benzylamine, N,N-diepoxypropyl-aminemethylcyclohexane, and the like. The addition ratio of the epoxy group-containing compound is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight, per 100 parts by weight of the polymer.

Further, the liquid crystal alignment agent of the present invention also contains a compound containing a functional decane. Examples of the compound containing a functional decane include 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 2-aminopropyltrimethoxydecane, and 2-aminopropyltri Ethoxy decane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, 3- Ureapropyltrimethoxydecane, 3-ureidopropyltriethoxydecane, N-ethoxycarbonyl-3-aminopropyltrimethoxydecane, N-ethoxyl Carbonyl-3-aminopropyltriethoxydecane, N-triethoxycarbenylpropyltriethylenetriamine, N-trimethoxymethylidenepropyltriethylenetriamine, 10-trimethoxymethyl矽alkyl-1,4,7-triazadecane, 10-triethoxycarbamido-1,4,7-triazadecane, 9-trimethoxycarbamido-3,6- Diazepine acetate, 9-triethoxycarbamido-3,6-diazaindolyl acetate, N-benzyl-3-aminopropyltrimethoxydecane, N- Benzyl-3-aminopropyltriethoxydecane, N-phenyl-3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyltriethoxydecane, N-double ( Oxyethylene)-3-aminopropyltrimethoxydecane, N-bis(oxyethylene)-3-aminopropyltriethoxydecane, and the like.

The addition ratio of these functional decane-containing compounds is preferably 40 parts by weight or less based on 100 parts by weight of the polymer.

<Liquid crystal display element>

The liquid crystal display element obtained by using the liquid crystal alignment agent of the present invention can be produced, for example, by the following method.

(1) The liquid crystal alignment agent of the present invention is applied to a substrate surface on which a patterned transparent conductive film is provided, for example, by a roll coating method, a spin coating method, a printing method, an inkjet method, or the like. Next, a coating film is formed by heating the coated surface. In addition, as the substrate, for example, glass such as floating glass or soda lime glass can be used; and polyethylene terephthalate, polybutylene terephthalate, polyether oxime, polycarbonate, or fat can be used. A transparent substrate made of plastic such as a cyclic polyolefin. As the transparent conductive film provided on the surface of the substrate, a NESA film (registered trademark of PPG, USA) and indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) made of tin oxide (SnO ₂ ) can be used. ITO film, etc. The pattern of the transparent conductive films forms a method that can be used by photolithography or a pre-mask. When the liquid crystal alignment agent is applied, the surface of the substrate and the adhesion between the transparent conductive film and the coating film are further improved, and a compound containing a functional decane or a compound containing a functional titanium may be applied to the surface of the substrate in advance. Wait. The heating temperature after application of the liquid crystal alignment agent is, for example, 80 to 300 ° C, more preferably 120 to 250 ° C. The liquid crystal alignment agent of the present invention containing polylysine can form a coating film as an alignment film by removing an organic solvent after coating. The film thickness of the liquid crystal alignment film formed is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

(2) On the surface of the formed coating film, for example, a cloth made of fibers such as nylon, rayon, or cotton is taken up into a cylindrical shape, and then rubbed in a certain direction. Thereby, the alignment of the liquid crystal molecules can be obtained to impart a liquid crystal alignment film to the coating film.

Further, the liquid crystal of the present invention is subjected to partial irradiation with ultraviolet rays as disclosed in JP-A-6-222366 or JP-A-6-281937, and the pretilt angle is changed. The photoresist film is partially formed on the rubbed liquid crystal alignment film, and the rubbing film is removed in a direction different from the preceding rubbing treatment, and the photoresist film is removed, as disclosed in Japanese Laid-Open Patent Publication No. H5-107544. The processing of the alignment of the liquid crystal alignment film can be performed to improve the visual field characteristics of the liquid crystal display element.

(3) Two substrates formed by the liquid crystal alignment film are formed, and the rubbing directions of the liquid crystal alignment films are orthogonal or antiparallel, and the two substrates are arranged opposite to each other with a cell gap. The peripheral part of the substrate is sealed The adhesive is applied to the liquid crystal cell by injecting liquid crystal into the gap defined by the surface of the substrate and the sealing agent, and sealing the injection hole to form a liquid crystal cell. On the outer surface of the liquid crystal cell, that is, on the outer side of each of the substrates constituting the liquid crystal cell, a liquid crystal display element is obtained by disposing a polarizing plate.

Among them, as the sealing agent, for example, a curing agent and an epoxy resin containing an alumina ball as a spacer can be used.

Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Further, a nematic liquid crystal is preferable, and for example, a Schiff base liquid crystal, an oxidized azo liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a triphenyl liquid crystal, or a combination can be used. A benzocyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cuba liquid crystal, or the like. Further, a cholesteric liquid crystal such as chlorinated gallbladder, cholestyl phthalate or cholestyl carbonate may be added to the liquid crystal, or the product name "C-15" or "CB-15" (manufactured by Merck) may be added. Used after the sale of palmar reagents. Further, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amine-2-methylbutylcinnamate may be used.

In addition, as a polarizing plate which is bonded to the outer surface of the liquid crystal cell, a polarizing plate in which a polyvinyl alcohol is stretched downward and a polarizing film which absorbs iodine and is called an H film is held by a cellulose acetate protective film, or the H film itself is exemplified. The resulting polarizer.

As described above, the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention exhibits a high voltage holding ratio as compared with the conventional alignment film, and exhibits a low focal mark at an arbitrary use temperature, and is suitable for forming a TN type liquid crystal display element. Various types of liquid crystal display elements such as STN liquid crystal display elements, reflective liquid crystal display elements, and transflective liquid crystal display elements.

The liquid crystal display element of the present invention can be effectively used in various devices, and can be applied to, for example, a display device such as a desktop computer, a wristwatch, a clock, a mobile phone, a counting display panel, a word processor, a personal computer, or a liquid crystal television.

Example

Hereinafter, the present invention will be more specifically illustrated by the examples, but the present invention is not limited by the examples. The oxime imidization ratio, voltage holding ratio, and coatability of the ruthenium iodide polymer in the examples and the comparative examples can be evaluated by the following methods.

[Method for determination of ruthenium imidization ratio of ruthenium iodide polymer]

The ruthenium iodide polymer was dried under reduced pressure at room temperature, dissolved in dimethyl hydrazine hydride, and tetramethyl decane was used as a reference material, and ¹ H-NMR was determined at room temperature by the following The formula shown in the formula (ii) is obtained.

Yttrium imidation rate (%) = (1-A ¹ /A ² ×α)×100------(ii)

A ¹ : peak area of protons from NH group (10 ppm)

A ² : peak area from other protons

α: the ratio of the number of other protons in a polymer precursor (poly-proline) to one NH matrix

[voltage retention rate]

The liquid crystal display element was subjected to 60 microseconds at a voltage of 5 V for an additional time, and after the addition was performed for 167 milliseconds, the voltage holding ratio after 167 milliseconds after the external release was measured. The measuring device used (share) VHR-1 manufactured by Dongyang Technica. When the voltage holding ratio was 95% or more, it was judged to be good, and otherwise, it was judged to be defective.

[Joint mark test]

As shown in Fig. 1, a unit cell having an ITO electrode was fabricated. A DC voltage of 6.0 V was applied to the electrode A, and a DC voltage of 0.5 V was applied to the electrode B, and the mixture was applied at room temperature and 80 ° C for 20 hours. After the pressure is released, the DC voltages of 0.1 to 3.0 V are applied to the electrodes A and B at a scale of 0.1 V. The scorch property was judged by the difference in luminance between the electrodes A and B of the respective voltages. When the luminance difference is large, it is judged that the scorch characteristic is poor.

Synthesis Example 1

2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride 110 g (0.5 mol) and 1,3,3a,4,5,9b-hexahydro-8-methyl-5 -(tetrahydro-2,5-dioxo-3-furan)naphtho[1,2-c]furan-1,3-dione 160g (0.5 mol), p-phenylene as diamine compound Diamine 96g (0.87 mole), 1,3-bis(3-aminopropyl)tetramethyldioxane 25g (0.1 mole), and 3,6-bis (4-aminobenzoic acid) 13 g (0.02 mol) of cholestane, 8.1 g (0.03 mol) of N-octadecylamine as a monoamine, dissolved in 960 g of N-methyl-2-pyrrolidone, and reacted at 60 ° C for 6 hours to obtain a solution viscosity of 60 mPa. . a poly-proline solution of s (this is called poly-proline (B-1)). Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution. After 400 g of pyridine and 410 g of acetic anhydride were added, the mixture was dehydrated and closed at 110 ° C for 4 hours. After the imidization reaction, the solvent in the system is solvent-substituted with unused γ -butyrolactone (the pyridine and acetic anhydride used in the imidization reaction in this operation are removed from the system) to obtain a solid component. The solution viscosity is 16.0 mPa when the concentration is 15.0% by weight and the solid content concentration is 6.0% by weight. s, hydrazine imidization rate of 95% of the imidized polymer "A-1" solution 1,500g.

Synthesis Example 2

190g (0.85 moles) and 1,3,3a,4,5,9b-hexahydro-8-methyl-5 as 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride -(tetrahydro-2,5-dioxo-3-furan)naphtho[1,2-c]furan-1,3-dione 47g (0.15 mol), p-phenylene as a diamine compound Diamine 92g (0.86 moles), 1,3-bis(3-aminopropyl)tetramethyldioxane 25g (0.1 mole), and 3,6-bis(4-aminobenzoic acid) 19 g (0.03 mol) of cholestane, 2.8 g (0.03 mol) of aniline as a monoamine, dissolved in 1,100 g of N-methyl-2-pyrrolidone, and reacted at 60 ° C for 6 hours to obtain a solution viscosity of 60 mPa. a poly-proline solution of s. Next, 3,900 g of γ -butyrolactone was added to the obtained polyamic acid solution, and 400 g of pyridine and 410 g of acetic anhydride were added, and the mixture was dehydrated and closed at 110 ° C for 4 hours. After the imidization reaction, the solvent in the system is substituted with an unused N-methyl-2-pyrrolidone (the pyridine and acetic anhydride used in the oxime imidization reaction of the operation are removed from the system). The viscosity of the solution is 16.0 mPa when the solid content concentration is 15.0% by weight and the solid content concentration is 6.0% by weight. The s, hydrazine imidization rate was 95%, and the imidized polymer (A-2) solution was 1,600 g.

Synthesis Example 3

220 g (1.0 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as a tetracarboxylic dianhydride, 110 g (0.99 mol) of p-phenylenediamine as a diamine compound, and gallium 7.8 g (0.015 mol) of cepalkyl-3,5-diamine benzoate was dissolved in N-methyl-2-pyrrolidone 3,100 g, and the reaction was carried out for 3 hours at room temperature to obtain a solution viscosity of 210 mPa. A poly-proline solution of s (this is called poly-proline (B-2)). Next, 3,400 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, and 400 g of pyridine and 300 g of acetic anhydride were added, and the mixture was dehydrated and closed at 110 ° C for 4 hours. After the imidization reaction, the solvent in the system is solvent-substituted with unused γ -butyrolactone (the pyridine and acetic anhydride used in the oxime imidization reaction of the present operation are removed from the system) to obtain a solid concentration. 9.0% by weight, the solid concentration of 3.1% by weight of the solution viscosity of 15.0mPa. s, yttrium imidization rate of 90% of the imidized polymer (A-3) solution 2,300g.

Synthesis Example 4

200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, 2,2'-dimethyl-4,4'- as a diamine compound 210 g (1.0 mol) of diamine biphenyl dissolved in 370 g of N-methyl-2-pyrrolidone and 3,300 g of γ -butyrolactone, and reacted at 40 ° C for 3 hours to obtain a solution viscosity of 160 mPa. A solution of poly-proline (referred to as poly-proline (B-3)).

Synthesis Example 5

2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride 110 g (0.5 mol) and 1,3,3a,4,5,9b-hexahydro-8-methyl-5 -(tetrahydro-2,5-dioxo-3-furan)naphtho[1,2-c]furan-1,3-dione 160g (0.5 mol), p-phenylene as diamine compound Diamine 82g (0.76 mole), bisaminopropyl tetramethyldioxane 25g (0.1 mole), 4-(4'-trifluoromethoxybenzylideneoxy)cyclohexyl-3, 5-diamine benzoate 35g (0.08 mol), and 4,4'-diamine diphenylmethane 9.9 g (0.05 mol), aniline as a monoamine 1.4 g (0.015 mol) dissolved in N -Methyl-2-pyrrolidone 1,300g, reacted at 60 ° C for 6 hours to obtain a solution viscosity of 55 mPa. s poly-proline. The obtained polylysine was dissolved in 2,500 g of N-methyl-2-pyrrolidone, 400 g of pyridine and 410 g of acetic anhydride were added, and the mixture was dehydrated and closed at 110 ° C for 4 hours. After the imidization reaction, the solvent in the system is substituted with an unused N-methyl-2-pyrrolidone (the pyridine and acetic anhydride used in the oxime imidization reaction of the present operation are removed from the system). The viscosity of the solution is 13.0 mPa when the solid content concentration is 17.0% by weight and the solid content concentration is 6.0% by weight. The s, hydrazine imidization rate was 95%, and the imidized polymer (A-4) solution was 1,800 g.

Example 1

Polyimine (A-1) obtained in Synthesis Example 1 and polylysine (B-3) obtained in Synthesis Example 4 were polyiminimide: polyglycine = 20:80 (weight ratio) Dissolved in a mixed solvent of γ -butyrolactone/N-methyl-2-pyrrolidone/butyl cellosolve (weight ratio 71/17/12), and dissolved 2 parts by weight of N, N, N for 100 parts by weight of the polymer. ',N'-tetraepoxypropyl-4,4'-diaminediphenylmethane, 200 parts by weight of the polymer, dissolved 2.5 parts by weight of the compound of the above formula (23) as an imidazole compound, as a solid The solution having a concentration of 6 wt% was thoroughly stirred, and the solution was filtered using a filter having a pore size of 1 μm to prepare a liquid crystal alignment agent of the present invention. The liquid crystal alignment agent is coated on a transparent conductive film provided with an ITO film on one surface of a glass substrate having a thickness of 1 mm, using a liquid crystal alignment film printer (manufactured by Nippon Photocopier Co., Ltd.). After drying on a hot plate at 80 ° C for 1 minute, it was dried on a hot plate at 200 ° C for 10 minutes to form a film having an average film thickness of 600 Å. Rubbing treatment was performed on the film by a friction machine having a roll wound with a rayon cloth at a drum rotation number of 400 rpm, a table moving speed of 3 cm/sec, and a bristle length of 0.4 mm. The liquid crystal alignment film-coated substrate was subjected to ultrasonic cleaning in ultrapure water for 1 minute, and then dried in a dust-free oven at 100 ° C for 10 minutes. Next, on the outer edge of the liquid crystal alignment film of the liquid crystal alignment film coating substrate having the pair of transparent electrode/transparent electrode substrates, an epoxy resin adhesive containing an alumina ball having a diameter of 5.5 μm is applied to form a liquid crystal alignment. The film faces are superposed and pressed against each other to harden the adhesive. Next, a liquid crystal injection port was filled between the substrates, and a nematic liquid crystal (manufactured by Merck Co., Ltd., MLC-6221) was filled, and then the liquid crystal injection port was sealed with an acrylic photocurable adhesive, and the polarizing plates were bonded to both sides of the substrate to produce a polarizing plate. Liquid crystal display element. The voltage holding ratio of the obtained liquid crystal display element was evaluated. The liquid crystal alignment agent obtained by the present invention exhibits a high value of a voltage holding ratio of 99% or more. Further, after the scorch test, a good result can be obtained regardless of any pressure temperature.

Example 2, 3 and Comparative Examples 1 to 10

The polyimine (A-1)~(A-4) and polylysine (B-1)~(B-3) obtained in Synthesis Examples 1 to 5 and N, N, N', N' - tetraepoxypropyl-4,4'-diaminediphenylmethane was dissolved in a mixed solvent containing γ -butyrolactone as a main component, and further in Examples 2 and 3 and Comparative Examples 1, 3, and 5. The imidazole compound represented by the above formula (24) was dissolved in 7, 9 to obtain a solution having a solid concentration of 6 wt%, and the solution was filtered through a filter having a pore size of 1 μm to prepare a liquid crystal alignment agent of the present invention. Using the thus-prepared liquid crystal alignment agent, a film was formed on the surface of the substrate in the same manner as in Example 1, and a liquid crystal display element was produced using the substrate on which the liquid crystal alignment film was formed. The voltage holding ratio is evaluated. Also, a scorch test was also performed. The results are shown in Table 1.

Fig. 1 is an explanatory view showing a unit cell having an ITO electrode which is formed by a burn test.

Claims (5)

A liquid crystal alignment agent characterized by having a polylysine having a guanine bond unit represented by the following formula (I-1) and a poly(imine bond unit) represented by the following formula (I-2) a polymer of a mixture of quinone imines, wherein the ratio of the number of oxime imine linkage units of the total number of bond units of the guanidine bond unit to the oxime bond unit is 10 to 80%, and contains the following formula (A) ) an imidazole compound as shown; (wherein P ¹ is a tetravalent organic group and Q ¹ is a divalent organic group) (wherein P ² is a tetravalent organic group and Q ² is a divalent organic group) (wherein R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group, and n is an integer of 0 to 3). The liquid crystal alignment agent of claim 1, wherein P ¹ or P ^{2 in} the formula contains self-selected from 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a,4,5 , 9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furan)-naphtho[1,2-c]-furan-1,3-dione and 1 The tetracarboxylic dianhydride in which 2,3,4-cyclobutanetetracarboxylic dianhydride is grouped removes the residue of the two acid anhydride groups. The liquid crystal alignment agent of claim 1 or 2, wherein 100 parts by weight of the polymer further contains 0.1 to 30 parts by weight of a compound having at least one epoxy group in the molecule. A liquid crystal alignment film characterized by being formed by a liquid crystal alignment agent according to any one of claims 1 to 3. A liquid crystal display element characterized by comprising a liquid crystal alignment film according to item 4 of the patent application.